Acid-catalyzed decomposition of aliphatic alcohols

ABSTRACT

Secondary and tertiary aliphatic alcohols when reacted with peracids, are converted to a mixture of ketones, aldehydes, and alcohols in high yields.

United States Patent [191 Turner et al. 5] Jan. 7, 1975 ACID-CATALYZED DECOMPOSITION OF 260/642 ALIPHATIC ALCOHOLS [75] Inventors: John O. Turner, Shavertown; References Cited Norman C. Deno, State College, OTHER PUBLICATIONS both of J. Hoffman et al., J.A.C.S.," Vol. 77, pp. [73] Assignee: Sun Ventures, Inc., St. Davids, Pa. 3,l393,l40, (1955).

i Fieser et al., "Reagents for Organic Synthesis," pp. [22] 1974 88-90, 456465 and 785-790, l18l19, (1967). [21] Appl. No.: 438,978

Related Us. Application Data Primary ExaminerBernard Helfin [60] Continuationinart of Ser No 301048 Oct 26 Assistant Examiner james Reamer 1972, abandonei i, which a divisioii of Sen No: Attorney Agent or Firm-George Church; Donald 98,035, Dec. 14, 1970, abandoned, which is a Johnson; Stanford Back continuation-in-part of Ser. No, 54,578, July 13, 1970, abandoned [57] ABSTRACT Secondary and tertiary aliphatic alcohols when rel l C 260/531 260/593 acted with peracids, are converted to a mixture of ke- [51] Int Cl Cmc 51/24 tones, aldehydes, and alcohols in high yields. [58] Field of Search 260/593 R, 531 R, 601 R, 4 Claims, N0 Drawings ACID-CATALYZED DECOMPOSITION OF ALIPHATIC ALCOHOLS CROSS-REFERENCE TO RELATED APPLICATION BACKGROUND OF THE INVENTION This invention relates to a novel process for the prep aration of ketones or aldehydes, and alcohols. More particularly, this invention relates to a process for the preparation of high yields of aliphatic alcohols and ketones by reacting tertiary aliphatic hydroperoxides and peroxides with a highly concentrated acid catalyst. In afurtherembodiment, secondary aliphatic hydroperoxides have been found to yield mixtures of alcohols, aldehydes and ketones of varying concentrations, depending upon the acid concentration employed.

Certain prior art teachings have shown that alkyl or aromatic hydroperoxides may be contacted with acids to form various reaction products, including alcohols and ketones, but the results have, at best, been characterized by low yields and mixtures of many different products. Thus, for example, Leffler, Chem. Revs. 45,385 (1949), suggested that the only products obtainable from the action of acids on tbutylhydroperoxide would be isobutylene and hydro gen peroxide. Maslennikov et al, Tr. Khim i Khim Ternol, 59 (1965), on the other hand, reacted tbutylhydroperoxide with benzene-sulfonic acid to obtain less than percent each of acetone and methanol. Similarly, Hoffman et al, J. Am. Chem. Soc., 77, 3139(1955) perpared neopentyl alcohol and acetone from isooctyl hydroperoxide using 65 to 70 percent H 50 but the yield of both of these products together was only about 40 percent. Finally, Turner et al, in copending application U.S. Ser. No. 2,681, filed Jan. 13, 1970, disclosed that when t-butylhydroperoxide was contacted with 50 to 60 weight percent sulfuric acid there was obtained a mixture of di-t-butylperoxide and hydrogen peroxide. It was also found that at 10 to weight percent concentration of sulfuric acid, no reaction whatsoever took place.

Using aromatic hydroperoxides as starting materials, Davies et al, J. Chem. Soc., 2204 (1954) reported that xanthhydryl peroxide was obtained by contacting glacial acetic acid with xanthhydryl hydroperoxide. Also, it is well known that cumene hydroperoxide forms a mixture of phenol and acetone using low acid concentrations. and essentially unusable decomposition products at high acid concentrations, i.e., at concentrations of above about 80 percent. See also, J. Chem. Soc., 3917(1956) which indicates that if cumene were treated under strongly acidic conditions the ring would be extensively sulfonated.

Thus, the possibility of obtaining high yields of ketones, aldehydes and'alcohols from aliphatic hydroperoxides using concentrated acid catalysts is neither taught nor suggested by the prior art. Rather, the effect of concentrated acids on aromatic hydroperoxides suggests a contrary result, as does the fact that lower concentrations of acids on aliphatic hydroperoxides yield hydrogen peroxide and di-alkylperoxides.

SUMMARY OF THE INVENTION 1 In accordance with the present invention, it has now been found that when tertiary aliphatic hydroperoxides and peroxides are contacted with highly concentrated acid catalyst, there is obtained a mixture of ketones and alcohols in high yields.

It has further been found that when secondary aliphatic hydroperoxides are reacted with varying concentrations of acid, the composition of the product mixture comprising alcohols, ketones, and aldehydes, is also varied markedly.

DESCRIPTION'OF THE INVENTION The reaction of the tertiary aliphatic hydroperoxide with the acid may be conveniently carried out by slowly adding the hydroperoxide (or corresponding peroxide) to the concentrated acid, preferably dropwise, at a temperature of about 0 to 20 C, and preferably form 0 to 10 C in order to control this highly exothermic reaction. Under these conditions, the reaction takes place virtually instantaneously. Under these conditions, also, the ratio of starting material to acid is not critical except for the fact that the acid should be maintained in substantial excess of the hydroperoxide as it is added to the acid in order that its concentration not fall below about percent. Desirably, the acid concentration should be maintained at about to 96 percent, and most preferably at concentrations of at least about percent when the starting material is a tertiary aliphatic hydroperoxide, although oleum solutions may be employed if desired. At concentrations below about 75 percent, when starting with an hydroperoxide, increasing amounts of the corresponding peroxides are formed.

The acids which may be used in the process of this invention include hydrochloric and sulfuric, as well as fluorosulfonic acid, acid-treated molecular sieves and the like. Of these, sulfuric acid and oleum are pre ferred.

The tertiary aliphatic hydroperoxide and peroxide starting materials include those compounds having from about three to 12 carbon atoms. The tertiary alkyl hydroperoxides are preferred since they are generally more reactive than the secondary compounds. Typical amongst the tertiary alkyl hydroperoxides are such compounds as t-butylhydroperoxide, t-pentylhydroperoxide, isooctyl hydroperoxide, and the like.

When these compounds are treated in accordance with this process there are obtained the corresponding ketones and alcohols, as for example, tbutylhydroperoxide or -peroxide yields acetone and methanol, while t-pentylhydroperoxide or -peroxide yields acetone and ethanol.

In a further embodiment of this invention it has been found that secondary aliphatic hydroperoxide may also be reacted with concentrated acids of at least about 70 percent concentration to obtain a product mixture of alcohols, ketones and aldehydes. However, unlike the tertiary aliphatic hydroperoxides, the type of compound and the proportions thereof vary markedly depending upon theacid concentration employed, as will be seen from the examples below.

The reaction employing these secondary aliphatic hydroperoxides is carried out in the same manner, with the same conditions and with the same acids as in'the case of the tertiary compounds. That is to say, the process is generally carried out by adding the hydroperoxide dropwise into the acid at a temperature of from to C. The ratio of hydroperoxide to acid is not critical but preferably the acid should be present in substantial excess of thehydroperoxide to maintain an acid concentration of at least 70 percent, and preferably above 85 percent up to 100 percent, or in the. case 0 sulfuric acid, in the form of oleum.

Again, the acids may include hydrochloric, sulfuric, fluorosulfonic acid and the like. Sulfuric acid is preferred.

The secondary aliphatic hydroperoxides, and preferably the alkyl hydroperoxides, include compounds having from about three to 12 carbon atoms. Typical amongst these are such compounds as 2- butylhydroperoxide, 2-pentylhydroperoxide, 3-pentylhydroperoxide and the like.

When these compounds arereacted with a concentrated acid of at least about 70-75 percent, and preferably higher, there are obtained not only alcohols and ketones, but in some cases, as described below, aldehydes as well. For example, 3-pentylhydroperoxide or -peroxide yields propanal, 3-pentanone, and ethanol. It has been determined that the reason for this is that such a product mixture is the result of both hydrogen and alkyl migration. It has further been found that the relative proportions of these productsmay be varied by varying the acid concentration. Thus, for example, using 96 percent sulfuric acid, in the case of 2- butylhydroperoxide, there is obtained a 48:48;4 percent yieldof 2-butanone; ethanol and acetaldehyde mixture; and methanol and propanal mixture respectively; whereas, for example, using 70 percent acid acid there is obtained an 82:18 yield 2-butanone and an ethanol-acetaldehyde mixture respectively; with no products formed as a result of methyl migration. As stated above, unlike tertiary aliphatic hydroperoxides, the reaction of secondary hydroperoxides with acids thus varies'with acid concentration and, depending upon the nature of the starting material, will produce aldehydes as well as alcohols and ketones.

It will be understood that in each case where an alcohol is formed, it is generally recovered as a salt corresponding to the acid employed. Thus, for example, when using sulfuric acid the ethanol is formed as ethyl ing the ketones from the alcohols.

In still another embodiment of this process, it has been found that when the acid catalyst employed is a peracid of the same concentrations as described above, such as persulfuric acid or the peracid obtained from mixing K S O and H SO it is possible to form the desired hydroperoxide starting material in situ from the corresponding alcohol. Thus, for example, when contacting t-butyl alcohol wih a molar equivalent of persulfuric acid, there is obtained a mixture of acetone and methanol. Ithas also been found, in accordance with this process, that when an excess of the peracid is used, and preferably at least two moles of acid, the acetone is further converted to acetic acid and additional methanol.

It will be understood that inasmuch as the process of this further embodiment involves the formation of hydroperoxide intermediates, in situ, that therefore the above-mentioned distinction between the tertiary alkyl hydroperoxides and secondary alkyl hydroperoxides applies equally to the reaction involving the corresponding alcohols. That is to say, when tertiary alkyl alcohols are reacted wih peracids at concentrations of at least about 90 percent, based on the weight of the total reaction mixture, the products obtained are ketones and alcohols, while the products of the corresponding secondary alkyl alcohols with a peracid of at least 70 percent concentration are ketones, aldehydes, and alcohols.

The following specific examples will. further serve to illustrate the nature, operation and advantages of the present invention. All percentages are on a weight basis. The reported yields are based on percent conversion of the hydroperoxide starting material.

In these examples, Examples 1-7 represent reactions employing tertiary aliphatic hydroperoxides, while Examples 8 and 9 represent the results obtained from secondary hydroperoxides.

EXAMPLE 1 The following comparative example illustrates the results obtained by contacting an hydroperoxide with 50 weight percent concentration of H SO Nine grams (0.1 moles), of t-butylhydroperoxide are added to 25 cc of 50 weight percent aqueous H 50 and stirred at 50 C for 15 hours. Phase separation yields 6.75 g. (.046 m) of di-t-butylperoxide (92 percent of theory) and a water white acid phase.

EXAMPLE 2 Four and one-half grams (0.05 moles) of -tbutylhydroperoxide are added dropwise with stirring to 12 cc of 96 percent H SO while maintained the temperature below 15 C. The hydroperoxide rearranges to give a 96 percent yield of acetone and methanol (analyzed quantitatively by NMR spectroscopy).

In accordance with the foregoing procedure, but substituting t-pentylhydroperoxide for tbutylhydroperoxide, there is obtained a mixture of acetone and ethanol in 84 percent yield, together withlesser amounts of methylethyl ketone and methanol.

Also, in accordance with the'foregoing procedure, but substituting isooctylhydroperoxide for butylhydroperoxide, there is obtained a mixture of neopentyl alcohol and acetone in an 85 percent yield.

EXAMPLE 3 Seven and three tenth. grams (0.05 moles) of di-t-, butyl)peroxide are added dropwise with stirring to 12 ccof 96'percent sulfuric acid while maintaining the temperature below 15 C. The peroxide reacts in a manner to yield 0.049 moles of both acetone and methanol. The remaining part of the peroxide molecule evolves as isobutene. When run under conditions which prevented loss of isobutene, isobutene polymerization and rearrangement products (cycloallylic ,carbonium ions) are sl so detected in the NMR spectrum.

- In accordance with the foregoing procedure, but substituting dFt-Pentylperoxide for t-butylperoxide, there is obtained predominantly a mixture of ethanol and acetone.

EXAMPLE 4 When the procedure of Example 3 is repeated but 120 percent fuming H 80 substituted for 96 percent H 50 the same products are obtained, i.e., acetone and methanol, together with some isobutene.

EXAMPLE 5 In accordance with the procedures of Example 2, but substituting fluorosulfonic acid for sulfuric acid, there is obtained a mixture of acetone and methanol in 96 percent yield. 1

Similarly. when perchloric acid is substituted for sulfuric acid in Example 2, a high yield of acetone and methanol is once again obtained.

EXAMPLE 6 Addition of 0.15 grams of t-butyl alcohol to 2 moles of a K S O H SO reagent (made by dissolving 10 grams of 5 0 in moles of 96 percent H 80 yields predominantly acetone and methanol (as methyl hydrogen sulfate) as shown by NMR spectrav In accordance with the foregoing procedure, but starting with a molar excess of acid reagent, there is obtained a mixture of acetone, methanol, acetic acid and some small amounts of methyl acetate, as shown by the NMR spectrum.

EXAMPLE 7 In accordance with the procedures of Example 7, but substituting t-amyl alcohol for t-buty1 alcohol, there is obtained a mixture of acetone and ethanol. When an excess of acid is employed, a mixture of acetone, ethanol, acetic acid and some methanol is obtained.

EXAMPLE 8 A series of runs is carried out wherein 0.93 grams (0.01 moles) of Z-butylhydroperoxide (92 percent pure) is added dropwise with stirring to 5 cc of sulfuric acid of the following concentrations: 70,80 and 96 per cent while maintaining the temperature below 10 C. The mole percent yield of products is as follows;

Hydrogen (a) Ethyl (b) Methyl (c) Concentration Migration Migration Migration (a) lbutanone resulting from hydrogen migration (b) ethyl hydrogen sulfate and acetaldehyde resulting from ethyl migration to) methyl hydrogen sulfate and npropanal resulting from methyl migration EXAMPLE 9 y In accordance with the procedures of Example 9, a series of runs is carried out with 3-pentylhydroperoxide in place of 2-butylhhdroperoxide. The mole percent yield of products is as follows:

(a) 3-pentanone from hydrogen migration (b) ethyl hydrogen sulfate and propanal from ethyl migration The invention claimed is:

l. A process for the preparation of ketones and alcohols which comprises contacting a secondary or tertiary alkyl alcohol having 3 to 12 carbon atoms with a peracid selected from the group consisting of persulfuric acid and the peracid obtained from mixing K 8 0 and H 80 said peracid having a concentration of not less than about weight percent based on the total weight of the reaction mixture.

2. The process according to claim 1 wherein the concentration of the acid is from about to 96 percent.

3. The process according to claim 1 wherein the alcohol is t-butyl alcohol.

4. The process according to claim 1 wherein an excess of acid is employed and there is recovered a product mixture containing ketones, alcohols and acids. 

1. A PROCESS FOR THE PREPARATION OF KETONES AND ALCOHOLS WHICH COMPRISES CONTACTING A SECONDARY OR TETIARY ALKYL ALCOHOL HAVING 3 TO 12 CARBON ATOMS WITH A PERACID SELECTED FROM THE GROUP CONSISTING OF PERSULFURIC ACID AND THE PERACID OBTAINED FROM MIXING K2S208 AND H2SO4, SAID PERACID HAVING A CONCENTRATION OF NOT LESS THAN ABOUT 75 WEIGHT PERCENT BASED ON THE TOTAL WEIGHT OF THE REACTION MIXTURE.
 2. The process according to claim 1 wherein the concentration of the acid is from about 80 to 96 percent.
 3. The process according to claim 1 wherein the alcohol is t-butyl alcohol.
 4. THE PROCESS ACCORDING TO CLAIM 1 WHEREIN AN EXCESS OF ACID IS EMPLOYED AND THERE IS RECOVERD A PRODUCT MIXTURE CONTAINING KETONES, ALCOHOLS AND ACIDS. 